This invention relates to a permanent, personal information carrier for insertion into a tooth or other mineralized part of a person's body, and, more particularly, to such a carrier in which the information of said carrier is directly readable by means of standard dental X-ray radiographs or the like and methods of making, installing and using same.
There are numerous techniques known for permanently marking a person by permanently affixing an information carrier to the person to be identified. There are two known basic techniques of affixing the carrier to the person, and they both usually employ means for attaching the carrier to a tooth because of its relative durability and accessability. In the first technique, the carrier is inserted into either a naturally occurring or manufactured cavity which is then filled with a filler to protectively seal the information carrier within the cavity. This provides maximum protection for the carrier.
Disadvantageously, with this first technique, it has not been known how to conceal the presence of the carrier while at the same time enabling reading of the carrier without first excavating it from the tooth. In U.S. Pat. No. 30,594 issued to Samis on Apr. 28, 1981, a radiographically detectable carrier is mounted at the bottom of a cavity made in the top of a tooth to be filled with an amalgam, and a radiopaque pin extending away from the amalgam is provided to radiographically mark the presence and location of the carrier; however, the code cannot be read. If it is desired to read the information of the carrier, it must be excavated carefully to minimize possible destruction of the information. Likewise, in U.S. Pat. No. 4,208,795 issued to Muhlemann et al. on June 24, 1980, the location in a tooth of an optically readable carrier is visually marked with an opaque, colored filler which must be dissolved, or the tooth must be fragmented, in order to excavate and remove the carrier. In U.S. Pat. No. 4,512,744 issued to Michnick et al. on Apr. 23, 1985, a microdot within a hole is readable by means of a visual scanner without excavation. However, the microdot is covered with a clear, transparent composite, and thus the presence of the microdot cannot be concealed from casual visual inspection. A similar technique to that of Michnick et al. is shown in U.S. Pat. No. 4,439,154 issued to Mayclin on Mar. 27, 1984, to mark removable dental prosthesis.
In the second known technique, information carrying marks or other indicia are attached to or inlaid into the surface of the tooth. This enables reading the information without first excavating the carrier, but, disadvantgeously, again the presence of the carrier cannot be concealed. In addition, since the carrier is not protectively enclosed within the tooth but is only on the surface, it is more susceptible to independent or inadvertent removal or destruction. In U.S. Pat. No. 4,557,693 issued to Elgger on Dec. 10, 1985, a carrier attached to the inside, or tongue side, surface of a tooth can be read through use of a special electronic photo-optical reader. In U.S. Pat. No. 3,925,896 issued to McDowell on Dec. 16, 1975, coded tines are inlaid into a surface of a tooth at selected radial positions to encode identifying information. Similarly, in U.S. Pat. No. 1,713,267 issued to Crowley on May 14, 1929, code numbers themselves are inlaid directly on the surface of a removable artificial tooth.
A principal problem with not concealing the presence of the carrier from casual visual inspection arises primarily in the case of kidnapping. In those instances, if the kidnapper discovers the presence of an identification marking on a child, in all likelihood the carrier will be removed, perhaps by removing the entire tooth. If the carrier is not detected and removed, then it may be detected in the course of routine dental X-rays which can then be reported to the appropriate authorities. However, in the absence of the ability to actually read the carrier information to provide positive identification and without approval to excavate and remove the carrier, there may be little authorities can do even if the presence of an information carrier is detected.
Another problem with known identification techniques is that in order to identify a corpse or amnesic, the information carrier must be detached from the person and cannot therefore be used for confirmatory identification at a later time.
Yet another problem with some of the above systems is that they require special experience and special code reading devices which are not generally available to dentists and others to read the information.